Method for rolling magnesium alloys



Patented Jan. 15, 1924.

PATENT OFFICE.

rumx THOMAS, or rmuKronrou-THn-Mam, GERMANY, assreuon 'ro THE mam GHEMISCHE ranmx enmsnum-ntnxa'aon, or rRANKroRr-ou-trHE-mAm, GER- MANY.-

IlllIE'flHZOD FOR ROLLING MAGNESIUM ALLOYS.

No Dmwing.

To all whom it may cor/teem;

Be it known that FELIX THOMAS, a citizen of the German Republic, residin at 53 Paul Ehrlichstrasse, Frankfort-one-Main,

Germany, has invented certain new and useful Improvements in the Method for Rolling Ma nesium Alloys (forwhich I have file application in Germany Aug. 21, 1919, application No. C. 28265), of which the followmg is a specification.

This invention relates to, a method for rolling magnesium alloys, especiallyalloys of magnesium with from 3-10% of zmc.

Alloys of magnesium containing smallamounts of zinc, which although in many respects closely resemble aluminium, as regards their physical and metallurgical.

properties, can nevertheless not be rolled like aluminium. Tn rolling sheets or bars of such alloys of magnesium containing small amounts of zinc, the material usually breaks in a direction approximately parallel to the axis of the rollers, or cracks are formed.

Experiments have shown that for rollingmagnesium alloys of the above-describe kind it is necessary to exercise greater care in maintaining the temperature during roll ing than is the case with any" other metal.

7 In particular it has been found that theprimary condition for a good rolling of bars out inthe heating furnace to about 220 250 (1 and this should. be repeated in ac.

cordance with the thickness of the sheet to be rolled, the metal being reheated after a.

certain number of passes. In practice the temperature of the reheating furnace is 40 kept, considerably higher, (approximately 400 (1), in order to accelerate the heating throughout and the necessary recrystallization of. the metal. The material to be rolled, which isIslightly superheated, is then cooled in the air and the beginning of the correct temperature range for rolling is ascertained by means of an acoustic method. This acoustic method is based on the fact that when the metal is too hot its sound is at first wooden when knocked against the rolling table, but when the correct rolling temperature is approached, the sound becomes metallic. 1

The fact that .exact temperature mainte- Application filed August 24, 1921 Serial No. 494,949.

I nance is necessary in rolling magnesium-zinc alloys, is one that could not be anticipated, the less so as pure magnesium can be rolled proportion as the temperature is higher.

What I claim and desire to secure b Letters Patent is 1. The method of rolling magnesium-zinc .at any temperature, and the more easily in 1 alloys which comprises submitting the alloy temperature.

2. The method of rolling magnesium-zinc alloys which comprises submitting the alloy to be rolled to heat in such a way that its temperature right. through is 220-250 CZ, thereupon passing said heated alloy at the said temperature through rolling mills and after a certain number of passes before furither rolling reheating the alloy so that it reaches the temperature of 220-250 0. right through. I

.3. The methodof rolling magnesium-zinc alloys which comprises heating the alloy to be rolled to a slightly higher temperature than that required-- for rolling the alloy so as to accelerate heating right through and the necessary recrystallization of the metal, thereupon coohng said alloy and as soon as the alloy has reached the temperature of to thin sheets is that the material to be rolled should be completely heated through-" 220-250 C. rolling said alloy.

- 4. The method of rolling magnesium-zinc a slightly higher temperature than that re-' quired for rolling so that the alloy is quickly heated right through, thereupon cooling in air, and as soon as the wooden sound ofv alloys which comprises heating the alloy to i the allo when knocked against the rolling table has changed to a metallic sound, rolling said alloy.

5 The-method of rollingmagnesium-zincv alloys which comprises submitting the alloy. to be rolled to heat in a furnace heated to a temperature of approximately 400 (1., thereupon cooling the alloy in air, and as soon as they alloy has reached the temperature of' 220-250 C., rolling said alloy.

6. The method of rolling magnesiumzinc alloys which comprises submitting the alloy to be rolled to heat in a furnace heated to a temperature of approximately 400 C., thereupon cooling the alloy in air, and as soon as the wooden sound of the alloy when knocked against the rolling table has changed to a metallic sound, rolling said alloy.

7. The method of rolling magnesium-zinc 5 alloys which comprises submitting the alloy to be rolledy-to heat in a furnace heated to 9 temperature which is higher vthan the temperature required for rolling, thereupon coolin the alloy to the temperature of 220- 250 6., rolling said alloy at said temperature .and after a, oertitin number of passes introducing said alloy into said heating furnace and repeating the cooling and rolling ogemtions. I

In testimony whereof I afiix m signature.

1 DR. FELIX Tl IOMAS. 

